So I and a girl were hanging out, going out to eat, cuddling, and having sex, and we both agreed to non-exclusivity and would talk to each other about the other hookups/etc. She was starting to get really coupley and lovey dovey with pet names...then would suddenly call me "friend" again...then act coupley again yada yada. I didn't understand it, but ultimately wanted an open relationship with her, with her as a gf/pseudo-gf with all the coupley stuff, and to fuck more casual friends on the side (which is what we've basically been doing, I guess). She was out on a date with my friend, at the same thing as me. I was jealous but, whatever, I could deal with sharing her since I was fucking other people too. We hung out and she mentioned feeling somewhat bad about sleeping around...then we were in bed and then she was suddenly in a death-themed depressive episode and had me leave with no explanation.

She'd been seeing me for a month, and another guy for a few weeks, and my friend for a week, and suddenly wants to be exclusive with my friend, and 'just friends' with me, and is becoming cold after constantly asking about my day and checking up on me. I have another other girls to fuck but don't have these feelings for them.